vec3.h

#ifndef VEC3H
#define VEC3H
//==================================================================================================
// Written in 2016 by Peter Shirley <ptrshrl@gmail.com>
//
// To the extent possible under law, the author(s) have dedicated all copyright and related and
// neighboring rights to this software to the public domain worldwide. This software is distributed
// without any warranty.
//
// You should have received a copy (see file COPYING.txt) of the CC0 Public Domain Dedication along
// with this software. If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
//==================================================================================================

#include <iostream>
#include <math.h>
#include <stdlib.h>


class vec3 {
    public:
        vec3() {}
        vec3(float e0, float e1, float e2) { e[0] = e0; e[1] = e1; e[2] = e2; }
        inline float x() const { return e[0]; }
        inline float y() const { return e[1]; }
        inline float z() const { return e[2]; }
        inline float r() const { return e[0]; }
        inline float g() const { return e[1]; }
        inline float b() const { return e[2]; }

        inline const vec3& operator+() const { return *this; }
        inline vec3 operator-() const { return vec3(-e[0], -e[1], -e[2]); }
        inline float operator[](int i) const { return e[i]; }
        inline float& operator[](int i) { return e[i]; }

        inline vec3& operator+=(const vec3 &v2);
        inline vec3& operator-=(const vec3 &v2);
        inline vec3& operator*=(const vec3 &v2);
        inline vec3& operator/=(const vec3 &v2);
        inline vec3& operator*=(const float t);
        inline vec3& operator/=(const float t);

        inline float length() const { return sqrt(e[0]*e[0] + e[1]*e[1] + e[2]*e[2]); }
        inline float squared_length() const { return e[0]*e[0] + e[1]*e[1] + e[2]*e[2]; }
        inline void make_unit_vector();

        float e[3];
};


inline std::istream& operator>>(std::istream &is, vec3 &t) {
    is >> t.e[0] >> t.e[1] >> t.e[2];
    return is;
}

inline std::ostream& operator<<(std::ostream &os, const vec3 &t) {
    os << t.e[0] << " " << t.e[1] << " " << t.e[2];
    return os;
}

inline void vec3::make_unit_vector() {
    float k = 1.0 / sqrt(e[0]*e[0] + e[1]*e[1] + e[2]*e[2]);
    e[0] *= k; e[1] *= k; e[2] *= k;
}

inline vec3 operator+(const vec3 &v1, const vec3 &v2) {
    return vec3(v1.e[0] + v2.e[0], v1.e[1] + v2.e[1], v1.e[2] + v2.e[2]);
}

inline vec3 operator-(const vec3 &v1, const vec3 &v2) {
    return vec3(v1.e[0] - v2.e[0], v1.e[1] - v2.e[1], v1.e[2] - v2.e[2]);
}

inline vec3 operator*(const vec3 &v1, const vec3 &v2) {
    return vec3(v1.e[0] * v2.e[0], v1.e[1] * v2.e[1], v1.e[2] * v2.e[2]);
}

inline vec3 operator/(const vec3 &v1, const vec3 &v2) {
    return vec3(v1.e[0] / v2.e[0], v1.e[1] / v2.e[1], v1.e[2] / v2.e[2]);
}

inline vec3 operator*(float t, const vec3 &v) {
    return vec3(t*v.e[0], t*v.e[1], t*v.e[2]);
}

inline vec3 operator/(vec3 v, float t) {
    return vec3(v.e[0]/t, v.e[1]/t, v.e[2]/t);
}

inline vec3 operator*(const vec3 &v, float t) {
    return vec3(t*v.e[0], t*v.e[1], t*v.e[2]);
}

inline float dot(const vec3 &v1, const vec3 &v2) {
    return v1.e[0] * v2.e[0]
         + v1.e[1] * v2.e[1]
         + v1.e[2] * v2.e[2];
}

inline vec3 cross(const vec3 &v1, const vec3 &v2) {
    return vec3(v1.e[1] * v2.e[2] - v1.e[2] * v2.e[1],
                v1.e[2] * v2.e[0] - v1.e[0] * v2.e[2],
                v1.e[0] * v2.e[1] - v1.e[1] * v2.e[0]);
}

inline vec3& vec3::operator+=(const vec3 &v){
    e[0] += v.e[0];
    e[1] += v.e[1];
    e[2] += v.e[2];
    return *this;
}

inline vec3& vec3::operator*=(const vec3 &v){
    e[0] *= v.e[0];
    e[1] *= v.e[1];
    e[2] *= v.e[2];
    return *this;
}

inline vec3& vec3::operator/=(const vec3 &v){
    e[0] /= v.e[0];
    e[1] /= v.e[1];
    e[2] /= v.e[2];
    return *this;
}

inline vec3& vec3::operator-=(const vec3& v) {
    e[0] -= v.e[0];
    e[1] -= v.e[1];
    e[2] -= v.e[2];
    return *this;
}

inline vec3& vec3::operator*=(const float t) {
    e[0] *= t;
    e[1] *= t;
    e[2] *= t;
    return *this;
}

inline vec3& vec3::operator/=(const float t) {
    float k = 1.0f/t;

    e[0] *= k;
    e[1] *= k;
    e[2] *= k;
    return *this;
}

inline vec3 unit_vector(vec3 v) {
    return v / v.length();
}


#endif